1,3-dimethyladamantane is expected to be useful as a material of various types of fine chemicals including pharmaceutical drugs, and a dicarboxylic acid and a diol thereof are expected to be useful as a highly functional polymer material.
Conventionally, Patent Document 1 describes hydrogenating acenaphthene represented by the following formula (3) to obtain perhydroacenaphthene (hereinafter, may be referred to simply as “PHA”) represented by the following formula (1) including four types of stereoisomers.

According to Patent Document 2, a method for obtaining 1,3-dimethyladamantane from PHA using a zeolite catalyst which is ion-exchanged with Ca and La and is containing Pt and Re, under the presence of H2 and HCl is known. However, the method of obtaining 1,3-dimethyladamantane from PHA has problems that the yield is as low as 38.7% and that Pt and Re in the catalyst are costly.
For producing adamantane with no substituent, a technology of using tetrahydrodicyclopentandiene as a material and using HF.BF3 as catalysts is known (see, for example, Patent Documents 3 and 4). However, no method of selectively producing 1,3-dimethyladamantane at a high yield by use of HF.BF3 catalysts is known so far.
For producing 1,3-dimethyladamantane by use of an acidic catalyst, a method of using aluminum chloride is known. However, in order to obtain 1,3-dimethyladamantane at a high yield, it is indispensable to use 1,2-dichloroethane, which is costly, as a catalyst component. In addition, aluminum chloride is not reusable and thus a large amount of waste derived from aluminum chloride is generated. For these reasons, the method of using aluminum chloride is not industrially advantageous (Patent Document 5).